In the early morning of November 28, 1953, 42-year-old Army scientist Frank Olson went out the window of a room in New York City’s Statler Hotel. Was it an accident, or an assassination?

Wormwood, the new Netflix true-crime documentary re-enactment series from director Errol Morris, investigates just that: Olson’s possible murder, and the conspiracy to cover up the death of a man who may have been ready to reveal government secrets. Among those possibly wishing to silence him: the C.I.A., President Gerald Ford’s chief and deputy chief of staff—Donald Rumsfeld and Dick Cheney, respectively—plus a rogue’s gallery of military men, a pseudo psychiatrist, and a magician.

“I sometimes describe Wormwood as a series of Russian nesting dolls—stories inside stories, inside stories, inside stories,” the Academy Award-winning documentarian says of his series, the title of which references both a line from Hamlet and a Bible passage. Two-plus years in the making, this innovative narrative from the director who pioneered many true-crime techniques—including the use of re-enactments and music—arrives December 15, just in time to satisfy our craving for an addictive nonfiction drama to binge during the shortest days of the year.

Morris’s inquiry began with his interest in a secret 1950s-60s C.I.A. program called “MK-Ultra,” which employed drugs and deception tactics—and most of whose records have been destroyed. “What we know about it is limited, and as a result, it has become catnip for conspiracy theorists”—though Morris is not one of them, he says.

Who Was Frank Olson?

Olson, a C.I.A. operative and bacteriologist played in Wormwood’s re-creation scenes by Peter Sarsgaard, may have taken part in secret government L.S.D. experiments—and could have been the subject of mind control. He may have also believed that the U.S used biological weapons during the Korean War, felt that he couldn’t live with that knowledge, and been ready to tell all.

Morris says Sarsgaard was his first and only choice to play Olson: “He jokes how I told him that what I liked most about his performances were his silences, and that is more or less true.” Molly Parker plays Olson’s tightly wound and devastated wife, Alice, whom we also see in archival footage. Having never known much about her husband’s confidential work, she ultimately slides into alcoholism. “My mother always said that the one thing she knew about my father’s state of mind was that he was very upset about Korea,” Olson’s son Eric Olson says in the series, during his documentary interview.

The Obsessed Storyteller

Now a Harvard-trained clinical psychologist, Eric was an impressionable 9-year-old when Olson’s boss and family friend, Lieutenant Colonel Vin Ruwet (played in re-creations by Scott Shepherd)—who may or may not have been with Olson when he died—came to the house early that November morning to inform the family of his death. Eric has been consumed with questions about what really happened to his father ever since. Morris underscores this by interviewing him sitting beneath a static analog clock, stopped precisely at the time his father died. “For me, it was like a bomb just dropped on my head,” Eric says in the series. “I was strongly identified with him at the time. And he just disappeared.”

Everything changed for Eric again after a 1974 New York Times story by Pulitzer Prize-winning journalist Seymour Hersh revealed that the C.I.A. had conducting a secret domestic surveillance program. A subsequent 1975 presidential review panel investigating the C.I.A.’s activities mentioned MK-Ultra—and said that an unnamed and “unwitting civilian” Army scientist had been surreptitiously given L.S.D. at some point before plummeting to his death in 1953. “What the ultimate goal is, is unclear,” Morris says of the panel’s findings. “Most likely the ultimate goal is to save the C.I.A. from itself. You could argue that it’s a kind of cover-up . . . and that’s when our story starts all over again.”

Especially for Eric, who was a graduate student by the time Hersh’s article was published. Shocked to learn there was more to his father’s death, he spearheaded efforts to uncover the truth, which resulted in the family’s unprecedented meeting with President Ford in the Oval Office. Ford apologized to the Olsons—but didn’t say for what. The family was urged not to sue, instead pushing government compensation, a course of action Morris believes Rumsfeld and Cheneyorchestrated. (He says it’s not clear whether Ford was a party to this or not.) A meeting with then-C.I.A. Director William Colby at Langley headquarters followed, during which Colby turned over documents supposedly detailing what happened to Olson. These documents are at the heart of Morris’s examination: “What really pleases me—yes, this is the kind of thing that deeply pleases me—is the documents might not be totally apocryphal, but part of them may be out-and-out fabrications and lies. . . I like the idea of dramatizing untruths as a way of thinking about what was true and was not.”

The Rogues’ Gallery of Men Around Olson

Over the course of the six-part series, a variety of scripted scenarios involving Olson and the men who knew and worked with him show different versions of possible events surrounding his death. In these fictionalized scenarios, we see men from Fort Detrick and the C.I.A. attend an offsite meeting at Deep Creek Lodge, where experiments with L.S.D. may have taken place. After Olson tries to quit his job, he tells Alice his colleagues want him to see a “psychiatrist” in New York City. Lieutenant Colonel Ruwet and chemist Robert Lashbrook (played by Christian Camargo) may have also traveled there; Eric also says that Lashbrook was a liaison to the C.I.A.’s Robert Gottlieb (Tim Blake Nelson)—who himself may have been involved in 1960s assassination plots, including those against Fidel Castro. The supposed shrink Olson sees, Dr. Harold Abramson (Bob Balaban), was an allergist who worked for the C.I.A., and was involved in the aerosolization of biological agents.

During the nine-day period they spent in New York City, Olson may have also been taken to see magician John Mulholland, who is said to have prepared a 50-page manual on deception and misdirection for the MK-Ultra project. “Mulholland was part of the Colby documents,” Morris explains. “You can say they’re all suspect. But it’s what we have. So, for example, when you see Frank freaking out at a performance of the Rodgers & Hammerstein show Me and Juliet, that’s in the documents.”

The Reporter Who May Have Been Played

Eric and Morris both agree that the story about Olson and L.S.D. was a red herring—one which investigative reporter Hersh swallowed whole, so to speak. Morris, who didn’t know Hersh, and had to “nag” him for more than a year and a half for him to get his participation in the documentary, says so plainly: “Was he played by the C.I.A.? Eric would probably argue that he was.” After Eric told Hersh as much in 2013, the journalist consulted a source; now he says he knows what happened to Olson, but can’t report it for fear of outing the informant.

The series ends on a conclusive note, but Morris also envisions an eventual epilogue to the story. “I believe that the assassination was ordered by the C.I.A., and I believe it came from the highest levels,” he says. “Examining the nature of the cover-up, and who was involved in the cover-up, is very much an ongoing investigation of mine. And I would say an ongoing investigation for Sy Hersh as well.”